题目内容
怎样简便怎样计算.
3.5-
|
25×(4+
|
|
6.4×9.9+6.4×
|
分析:(1)根据减法的性质简算;
(2)运用乘法分配律简算;
(3)先算乘法,再算加法;
(4)运用乘法分配律简算.
(2)运用乘法分配律简算;
(3)先算乘法,再算加法;
(4)运用乘法分配律简算.
解答:解:(1)3.5-
-
,
=3.5-(
+
),
=3.5-1,
=2.5;
(2)25×(4+
),
=25×4+25×
,
=100+15,
=115;
(3)
+
×
,
=
+
,
=1;
(4)6.4×9.9+6.4×
,
=6.4×9.9+6.4×0.1,
=6.4×(9.9+0.1),
=6.4×10,
=64.
1 |
3 |
2 |
3 |
=3.5-(
1 |
3 |
2 |
3 |
=3.5-1,
=2.5;
(2)25×(4+
3 |
5 |
=25×4+25×
3 |
5 |
=100+15,
=115;
(3)
3 |
5 |
4 |
5 |
1 |
2 |
=
3 |
5 |
2 |
5 |
=1;
(4)6.4×9.9+6.4×
1 |
10 |
=6.4×9.9+6.4×0.1,
=6.4×(9.9+0.1),
=6.4×10,
=64.
点评:此题主要考查分数的四则混合运算的运算顺序,以及应用运算定律进行简便计算的能力.
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